MySQL_(Java)分頁查詢MySQL中的數據

 

 

　　MySQL_(Java)使用JDBC向數據庫發起查詢請求　　傳送門

　　MySQL_(Java)使用JDBC創建用戶名和密碼校驗查詢方法　　傳送門

　　MySQL_(Java)使用preparestatement解決SQL注入的問題　　傳送門

 

　　MySQL數據庫中的數據，數據庫名garysql，表名garytb，向數據庫中添加多行數據　　

 

　　使用limit做數據查詢：limit [位置偏移量,]行數

　　位置偏移量是從，哪一行開始（行數從0開始），行數是指查詢幾行

　　從第四行開始查詢三行，用戶ID從1開始

　　

　　如果要查詢 第7頁，每頁8行
　　起始和末尾行數
　　0-7 第一頁
　　8-15 第二頁
　　16-23 第三頁
　　...
　　起始行數為 （頁數-1）*8

 

 　　通過JDBC對MySQL中的數據用戶名和密碼進行分頁查詢，查詢第四頁，沒頁顯示八行數據

 

 

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBC01 {

    public static void main(String[] args) throws SQLException  {
        //查詢第四頁，每頁顯示八行數據
        selectUserByPage(4,8);
    }

    public static void selectAll() throws SQLException {
        //注冊驅動    使用驅動連接數據庫
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            
            //String url ="jdbc:mysql://localhost:3306/garysql";
            //指定編碼查詢數據庫
            String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false";
            String user = "root";
            String password = "123456";
            //建立和數據庫的連接
            con = DriverManager.getConnection(url,user,password);
            
            //數據庫的增刪改查
            stmt = con.createStatement();
            //返回一個結果集
            rs =stmt.executeQuery("select * from garytb");
            
            while(rs.next()) {
                //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3));
                System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password"));
            }
        
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(rs!=null)
                rs.close();
            if(stmt!=null)
                stmt.close();
            if(con!=null)
                con.close();
        }
    }

    public static boolean  selectByUernamePassword(String username,String password) throws SQLException {
        Connection con=null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            
            String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false";
            con = DriverManager.getConnection(url,"root","123456");
            stmt =con.createStatement();
            String sql = "select * from garytb where username = '"+username+"' and password = '"+password+"'";
            //System.out.println(sql);
            rs = stmt.executeQuery(sql);
            
            if(rs.next()) {
                return true;
            }else {
                return false;
            }
                
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(rs!=null)
                rs.close();
            if(stmt!=null)
                stmt.close();
            if(con!=null)
                con.close();
        }
        
        return false;
    }

    public static boolean selectByUP2(String username,String password) throws SQLException{
        Connection con=null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            
            String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false";
            con = DriverManager.getConnection(url,"root","123456");
            
            String sql = "select * from garytb where username = ? and password = ?";
            PreparedStatement pstmt = con.prepareStatement(sql);
            //添加參數
            pstmt.setString(1, username);
            pstmt.setString(2, password);
            //進行查詢
            rs = pstmt.executeQuery();
                
            if(rs.next()) {
                return true;
            }else {
                return false;
            }
                
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(rs!=null)
                rs.close();
            if(stmt!=null)
                stmt.close();
            if(con!=null)
                con.close();
        }
        
        return false;
    }

    //pageNumber是頁數，第幾頁，pageCount是每頁顯示多少個數據
    public static void selectUserByPage(int pageNumber,int pageCount) throws SQLException {
        //注冊驅動    使用驅動連接數據庫
                Connection con = null;
                PreparedStatement stmt = null;
                ResultSet rs = null;
                try {
                    Class.forName("com.mysql.jdbc.Driver");
                    
                    //String url ="jdbc:mysql://localhost:3306/garysql";
                    //指定編碼查詢數據庫
                    String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false";
                    String user = "root";
                    String password = "123456";
                    //建立和數據庫的連接
                    con = DriverManager.getConnection(url,user,password);
                    
                    stmt = con.prepareStatement("select * from garytb limit ?,?");
                    stmt.setInt(1, (pageNumber-1)*pageCount );
                    stmt.setInt(2, pageCount);
                    
                    rs = stmt.executeQuery();
                    
                    while(rs.next()) {
                        //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3));
                        System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password"));
                    }
                
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }finally {
                    if(rs!=null)
                        rs.close();
                    if(stmt!=null)
                        stmt.close();
                    if(con!=null)
                        con.close();
                }
    }
}

 

　　使用PreparedStatement防止SQL注入

                    stmt = con.prepareStatement("select * from garytb limit ?,?");
                    stmt.setInt(1, (pageNumber-1)*pageCount );
                    stmt.setInt(2, pageCount);
                    
                    rs = stmt.executeQuery();
                    
                    while(rs.next()) {
                        //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3));
                        System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password"));
                    }

 

//pageNumber是頁數，第幾頁，pageCount是每頁顯示多少個數據
    public static void selectUserByPage(int pageNumber,int pageCount) throws SQLException {
        //注冊驅動    使用驅動連接數據庫
                Connection con = null;
                PreparedStatement stmt = null;
                ResultSet rs = null;
                try {
                    Class.forName("com.mysql.jdbc.Driver");
                    
                    //String url ="jdbc:mysql://localhost:3306/garysql";
                    //指定編碼查詢數據庫
                    String url ="jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false";
                    String user = "root";
                    String password = "123456";
                    //建立和數據庫的連接
                    con = DriverManager.getConnection(url,user,password);
                    
                    stmt = con.prepareStatement("select * from garytb limit ?,?");
                    stmt.setInt(1, (pageNumber-1)*pageCount );
                    stmt.setInt(2, pageCount);
                    
                    rs = stmt.executeQuery();
                    
                    while(rs.next()) {
                        //System.out.println(rs.getString(1)+","+rs.getString(2)+","+rs.getString(3));
                        System.out.println(rs.getString("id")+","+rs.getString("username")+","+rs.getString("password"));
                    }
                
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }finally {
                    if(rs!=null)
                        rs.close();
                    if(stmt!=null)
                        stmt.close();
                    if(con!=null)
                        con.close();
                }
    }